Diagnosis of supra‐esophageal gastric reflux: correlation of oropharyngeal pH with esophageal impedance monitoring for gastro‐esophageal reflux

Background Oropharyngeal (OP) pH monitoring has been developed as a new way to diagnose supra‐esophageal gastric reflux (SEGR), but has not been well validated. Our aim was to determine the correlation between OP pH and gastro‐esophageal reflux (GER) events detected by multichannel intraluminal impedance‐pH (MII‐pH). Methods Fifteen patients (11 males, median age 10.8 years) with suspected GER were prospectively evaluated with ambulatory 24‐h OP pH monitoring (positioned at the level of the uvula) and concomitant esophageal MII‐pH monitoring. Potential OP events were identified by the conventional pH threshold of <4 and by the following alternative criteria: (i) relative pH drop >10% from 15‐min baseline and (ii) absolute pH drop below thresholds of <5.5, 5.0, and 4.5. The 2‐min window preceding each OP event was analyzed for correlation with an episode of GER detected by MII‐pH. Key Results A total of 926 GER events were detected by MII‐pH. Application of alternative pH criteria increased the identification of potential OP pH events; however, a higher proportion of OP events had no temporal correlation with GER (45–81%), compared with the conventional definition of pH < 4 (40%). A total of 306 full‐column acid reflux episodes were detected by MII‐pH, of which 10 (3.3%) were also identified by OP pH monitoring. Conclusions & Inferences Use of extended pH criteria increased the detection of potential SEGR events, but the majority of decreases in OP pH were not temporally correlated with GER. Oropharyngeal pH monitoring without concurrent esophageal measurements may overestimate the presence of SEGR in children.     

Failure to respond to physiologic challenge characterizes esophageal motility in erosive gastro‐esophageal reflux disease

Background Non‐specific esophageal dysmotility with impaired clearance is often present in patients with gastro‐esophageal reflux disease (GERD), especially those with erosive disease; however the physio‐mechanic basis of esophageal dysfunction is not well defined. Methods Retrospective assessment of patients with erosive reflux disease (ERD; n = 20) and endoscopy negative reflux disease (ENRD; n = 20) with pathologic acid exposure on pH studies (>4.2% time/24 h) and also healthy controls (n = 20) studied by high resolution manometry. Esophageal motility in response to liquid and solid bolus swallows and multiple water swallows (MWS) was analyzed. Peristaltic dysfunction was defined as failed peristalsis, spasm, weak or poorly coordinated esophageal contraction (>3 cm break in 30 mmHg isocontour). Key Results Peristaltic dysfunction was present in 33% of water swallows in controls, 56% ENRD and 76% ERD respectively (P < 0.023 vs controls, P = 0.185 vs ENRD). The proportion of effective peristaltic contractions improved with solid compared to liquid bolus in controls (18%vs 33%, P = 0.082) and ENRD (22%vs 54%, P = 0.046) but not ERD (62%vs 76%, P = 0.438). Similarly, MWS was followed by effective peristalsis in 83% of controls and 70% ENRD but only 30% ERD patients (P < 0.017 vs controls and P < 0.031 vs ENRD). The association between acid exposure and dysmotility was closer for solid than liquid swallows (r = 0.52 vs 0.27). Conclusions & Inferences Peristaltic dysfunction is common in GERD. ERD patients are characterized by a failure to respond to the physiologic challenge of solid bolus and MWS that is likely also to impair clearance following reflux events and increase exposure to gastric refluxate.     

The frequency of apneas in very preterm infants is increased after non‐acid gastro‐esophageal reflux

Background To evaluate whether physical and/or chemical features of gastro‐esophageal reflux (GER) influence its relationship with apnea of prematurity (AOP). Methods Fifty‐eight preterm newborns (GA ≤33 weeks) with recurrent apneas were studied by simultaneous polysomnography and combined impedance and pH monitoring, to analyze whether the correlation between GER and AOP varies according to the acidity, duration and height of GERs. Key Results The frequency of apnea (number apnea/min) occurring after‐GER [median (range) 0.07 (0–0.25)] was higher than the one detected in GER‐free period [0.06 (0.04–0.13), P = 0.015], and also than the one detected before‐GER [0 (0–0.8), P = 0.000]. The frequency of apneas detected in the 30’’ after pH‐GER [median (range), 0 min^?1 (0–1.09)] was higher than the frequency detected in the 30’’ before [0 (0–0.91), P = 0.04]; even more, the frequency of apneas detected after non‐acid MII‐GER episodes [0 (0–2)] was significantly higher than the one detected before [0 (0–1), P = 0.000], whereas the frequency of apneas detected before acid MII‐GER episodes [0 (0–0.67)] did not differ from the one detected after [0 (0–2), P = 0.137]. The frequency of pathological apneas detected in the 30’’ after‐GER (0 min^?1, range 0–0.55) was higher than the frequency detected before (0, range 0–0.09; P = 0.001). No difference in mean height or in mean duration was found between GERs correlated and those non‐correlated to apnea. Conclusions & Inferences Non‐acid GER is responsible for a variable amount of AOP detected after‐GER: this novel finding must be taken into consideration when a therapeutic strategy for this common problem is planned.     

New insights into pharyngo‐esophageal bolus transport revealed by pressure‐impedance measurement

Background Pharyngeal propulsion, strength of peristalsis and esophago–gastric junction (EJG) resistance are determinants of esophageal bolus transport. This study used pressure‐impedance methods to correlate pharyngo‐esophageal function with the esophageal bolus trajectory pathway and pressures generated during bolus transport. Methods Pharyngo‐esophageal pressure‐impedance measurements were performed in 20 healthy adult controls. Pharyngeal automated impedance manometry (AIM) analysis was performed to derive pharyngeal swallow function variables. The esophageal time of nadir impedance (TZn) was used to track bolus trajectory pathway. The inflection, or flow stasis point (FSP), of the trajectory curve was determined as were the pressures within the bolus (PZn) above and below the FSP. The size of 20 mmHg isocontour defect (20 mmHg IC defect) measured the integrity of the peristaltic wave. Key Results For viscous boluses, weaker pharyngeal bolus propulsion correlated with the FSP being located higher in the esophagus. Pressure within the bolus was observed to increase at the FSP and below the FSP in a manner that correlated with the magnitude of esophageal peak pressures. Larger 20 mmHg IC defects were associated with lower pressures within the bolus at the FSP and below. Conclusions & Inferences The FSP of the bolus trajectory pathway appears to represent a switch from bolus propulsion due to pharyngeal mechanisms to bolus propulsion due to esophageal mechanisms. 20 mmHg IC defects significantly reduce bolus driving pressure at or below the FSP.